Blood and tissue zinc levels in spontaneously hypertensive rats

Zinc (Zn) determinations were performed on blood plasma and red cells, liver, heart, adrenals, and spleen of spontaneously hypertensive (SHR) and control normotensive (WKY) male rats, 20 weeks of age. SHR revealed higher red cell (p = 2 x 10(-5)) and heart (p = 0.007) Zn levels than WKY rats. The water content of organs was the same in the two strains. When compared with published data, these results suggest an association between high cell Zn levels and hypertension, the meaning of which is briefly discussed.     

大气PM_(2.5)对大鼠心血管系统的急性毒性作用

目的观察大气PM2.5对机体心血管系统的影响,比较PM2.5对不同生理、病理状态下大鼠心血管系统毒性的差异。方法在上海市非工业区采集大气PM2.5,选取SH和WKY大鼠各24只,采用气管滴注染毒方法给大鼠肺灌注不同剂量PM2.5,观察PM2.5对不同机体心血管系统的急性毒作用,测量染毒后动物血清心肌酶学(乳酸脱氢酶LDH和肌酸激酶同工酶CK-MB)及血压、心率、心电图。结果大鼠PM2.5染毒后,测定大鼠血清心肌酶发现,WKY和SH大鼠血清LDH和CK-MB随染毒剂量增加而增加,且与对照组相比有统计学差异;同时SH大鼠各实验组心肌酶含量除CK-MB的低剂量组外均高于WKY大鼠的相应组含量,表明PM2.5对SHR的心血管毒性作用可能大于对WKY大鼠的作用。此外,两种大鼠肺灌注PM2.5后血压和心率与对照组相比有明显改变,且染毒后大鼠心电图ST段与T波发生改变。结论结果提示暴露于PM2.5对机体心血管系统有一定的损伤作用,心肌出现缺血缺氧反应。     

The role of the sympathetic nervous system in radiation-induced apoptosis in jejunal crypt cells of spontaneously hypertensive rats

To evaluate the effect of the sympathetic nervous system on radiation-induced apoptosis in jejunal crypt cells, apoptosis levels were compared in spontaneously hypertensive rats (SHR), animals which are a genetic hyperfunction model of the sympathetic nervous system, and normotensive Wistar-Kyoto rats (WKY). SHR and WKY were exposed to whole body X-ray irradiation at doses from 0.5 to 2 Gy. The apoptotic index in jejunal crypt cells was significantly greater in SHR than in WKY at each time point after irradiation and at each dose. WKY and SHR were treated with reserpine to induce sympathetic dysfunction, and were subsequently exposed to irradiation. Reserpine administration to SHR or WKY resulted in a significant suppression of apoptosis. p53 accumulation was detected in the jejunum in both WKY and SHR after irradiation by Western blotting analysis. There were no significant differences in the levels of p53 accumulation in irradiated intestine between WKY and SHR. These findings suggested that hyperfunction of the sympathetic nervous system is involved in the mechanism of high susceptibility to radiation-induced apoptosis of the jejunal crypt cells.     

Dietary (n-3) fat and cholesterol alter tissue antioxidant enzymes and susceptibility to oxidation in SHR and WKY rats

Previously, 8% fish oil blend diets, compared to butter and soybean oil blend diets, reduced specific antioxidant enzyme activities and tissue susceptibility to in vitro oxidative stress in spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats. Moreover, high cholesterol (5.0 g/kg diet) diets protected against in vitro tissue lipid oxidation. In this study, we hypothesized that 160 g fat/kg diet as blends of (n-6) or (n-3) oils and cholesterol would alter antioxidant enzyme activities and thus increase tissue susceptibility to oxidation. The effects of diet blends of saturated (butter, B), (n-6) (soybean oil, SBO) or (n-3) (menhaden oil, MO) oils with cholesterol (0.5 or 5.0 g/kg) on systolic blood pressure (SBP), plasma lipids, antioxidant enzymes and susceptibility to oxidation were examined in SHR and WKY rats. SBP at 13 wk of age was greater (P < 0.001) in SHR than in WKY rats, but was not affected by diets. Plasma cholesterol and triacylglycerols were decreased (P < 0.001) by MO diets. Hepatic glutathione reductase activities were reduced (P < 0.001) in SBO-fed SHR and enhanced in SBO- and MO-fed WKY rats. Glutathione levels were reduced (P < 0.001) in RBC and enhanced (P < 0.001) in livers of MO-fed rats. Lipid oxidation was enhanced (P < 0.001) in red blood cells (RBC) from SBO groups, and hearts and livers of MO groups. High cholesterol diets reduced (P < or = 0.001) susceptibility to lipid peroxidation in RBC and liver of SHR and WKY rats. Greater amounts of dietary (n-3) fat enhance tissue susceptibility to oxidation, which can be modulated by increased dietary cholesterol in SHR and WKY rats.     

Effects of long-term administration of hesperidin and glucosyl hesperidin to spontaneously hypertensive rats

Hesperidin (HES) is a flavonoid contained in citrus fruit peel. We investigated the effects of long-term administration of HES and its newly developed water soluble analogue, glucosyl hesperidin (GHES), to spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Animals were fed with diets containing HES or GHES (30 mg/d/kg body weight) for 25 wk. While the daily food intake and the body weight of administered rats were not different from those of the non-administered control rats in both SHR and WKY through the experimental period, the blood pressure and heart rate of SHR administered HES or GHES for longer than 15 wk decreased as compared to the control group. The blood pressure and heart rate of WKY were not changed by the long-term administration of HES or GHES. These results suggest that HES and GHES have anti-hypertensive effects on hypertensive animals.     

Candesartan治疗对SHR大鼠心肌AngⅡ及其受体表达的影响

目的观察Candesartan早期治疗对SHR大鼠心肌纤维化及心肌AT1、AT2表达的影响,探讨其抗心肌纤维化的机制。方法选取4周龄的雄性自发性高血压大鼠SHR（Spontanous Hypertensive Rat,SHR）及与之年龄性别相配的正常大鼠WKY;动物分组：WKY组、SHR组、Candesartan治疗组（SHR—Can组,给药4周后停药,继续喂养至24周）;尾袖法测定大鼠血压,断头取血,称量全心与左心质量,计算心体比与左室质量指数;放免法测定血浆及心肌AⅡ水平;免疫组化法检测心肌组织中AT1、AT2的表达;Western blotting法测定心肌AT1、AT2的表达水平;天狼星红染色测定心肌胶原指数。结果8周龄后,与SHR组相比,SHR—Can组血压明显下降并持续24周（P〈0．05）;HR-Can组心体比及左室质量指数明显低于SHR组（P〈0．05）;SHR组血浆中AⅡ水平与WKY组相比明显增高（P〈0．01）,SHR—Can组与SHR组相比降低（P〈0．05）;心肌组织AⅡ含量SHR—Can组明显低于SHR组（P〈0．05）。心肌免疫组化染色示：与WKY相比,SHR大鼠AT1、AT2明显增高（P〈0．05）;与SHR相比,SHR-Can组心肌中AT1、AT2明显减少（P〈0．05）。Western blotting结果示：SHR组AT1、AT2表达水平明显高于WKY组（P〈0．05）;SHR—Can组AT1、AT2表达水平明显降低（P〈0．05）。天狼星红染色心肌胶原含量SHR—Can组明显低于SHR组（P〈0．05）。结论Candesartan早期治疗可抑制SHR大鼠高血压的形成与发展,也可抑制SHR心肌纤维化并降低心脏指数,还能降低SHR心肌AT1、AT2的表达,Candesartan抑制心肌纤维化可能与心肌局部AT1、AT2表达水平有关。     

Effects of sidestream cigarette smoke exposure on baroreflex components in spontaneously hypertensive rats

We evaluated short-term effects of sidestream cigarette smoke (SSCS) exposure on baroreflex function in spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) normotensive rats. Rats were exposed to SSCS during three weeks, 180 min, five days per week, in a concentration of carbon monoxide (CO) between 100 and 300 ppm. We observed that SSCS exposure increased tachycardic peak and heart rate range while it attenuated bradycardic reflex in WKY. In respect to SHR, SSCS also increased tachycardic peak. Taken together, our data suggests that three weeks of exposure to SSCS affects the sympathetic and parasympathetic component of the baroreflex in normotensive WKY while it tended to affect the sympathetic component in SHR.     

Disturbances of magnesium metabolism in the spontaneously hypertensive rat

Magnesium balance, and plasma and urinary levels, were studied in spontaneously hypertensive (SHR), Wistar Kyoto (WKY) and in Wistar (WI) rats. We found few differences in the measured parameters between WKY and WI rats, but the SHR rat which similarly maintained Mg balance has lower plasma Mg levels and less urinary Mg excretion. These abnormalities could favor establishment or maintenance of hypertension.     

The status of cellular analysis.

Magnesium balance, and plasma and urinary levels, were studied in spontaneously hypertensive (SHR), Wistar Kyoto (WKY) and in Wistar (WI) rats. We found few differences in the measured parameters between WKY and WI rats, but the SHR rat which similarly maintained Mg balance has lower plasma Mg levels and less urinary Mg excretion. These abnormalities could favor establishment or maintenance of hypertension.     

Effect of a methionine-supplemented diet on the blood pressure of Wistar-Kyoto and spontaneously hypertensive rats

The objectives of the present work were to evaluate the effect of a methionine-supplemented diet as a model of hyperhomocysteinaemia on the systolic blood pressure (BP) and vasomotor functions of aortic rings in Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). WKY and SHR rats, randomised into four groups, were fed a normal semisynthetic diet or a methionine (8 g/kg)-supplemented diet for 10 weeks. Systolic BP was measured non-invasively. At the end of the experiment, plasma homocysteine, methionine, cysteine and glutathione levels were determined. Vasoconstriction and vasodilatation of aortic rings were measured. The methionine-supplemented diet induced a significant increase in plasma homocysteine and methionine concentration in both WKY and SHR rats, an increase in plasma cysteine concentrations in WKY rats and an increase in the glutathione concentration in SHR. The systolic BP of WKY rats fed the methionine-supplemented diet increased significantly (P<0.01), whereas systolic BP was reduced in SHR. An enhanced aortic responsiveness to noradrenaline and a decreased relaxation induced by acetylcholine and bradykinin were observed in the WKY rats fed the methionine-enriched diet. In SHR, the bradykinin-induced relaxation was reduced, but the sodium nitroprusside response was increased. In conclusion, a methionine-enriched diet induced a moderate hyperhomocysteinaemia and an elevated systolic BP in WKY rats that was consistent with the observed endothelial dysfunction. In SHR, discrepancies between the decreased systolic BP and the vascular alterations suggest more complex interactions of the methionine-enriched diet on the systolic BP. Further investigations are needed to understand the paradoxical effect of a methionine-rich diet on systolic BP.     

The effect of diets adequate and deficient in calcium on blood pressures and the activities of intestinal and kidney plasma membrane enzymes in normotensive and spontaneously hypertensive rats

Basolateral and brush-border membranes were prepared from the intestines and kidneys of spontaneously hypertensive (SHR) and normotensive (WKY) rats fed on a calcium-adequate diet and assayed for their enzyme activities. In intestinal basolateral membranes the activities of Na+ K(+)-ATPase (EC 3.6.1.37) Ca2(+)-ATPase (EC 3.6.1.38) and alkaline phosphatase (EC 3.1.3.1) were lower in SHR rats when compared with WKY rats, whilst 5'-nucleotidase (EC 3.1.3.5) (a marker for basolateral membranes) was unaffected. In kidney basolateral membranes all enzymes were similar in activity in SHR and WKY rats. In intestinal brush-border membranes the activities of Ca2(+)-ATPase and alkaline phosphatase were lower in SHR rats when compared with WKY rats, whilst microvillus aminopeptidase (EC 3.4.11.2) (a marker for brush-border membranes) was unaffected. In kidney brush-border membranes all enzymes were similar in activity in SHR and WKY rats. The blood pressures of the SHR rats were considerably higher than those of the WKY rats. When SHR rats were fed on a Ca-deficient diet the activities of Na+K(+)-ATPase, Ca2(+)-ATPase and alkaline phosphatase in basolateral membranes and Ca2(+)-ATPase and alkaline phosphatase in brush-border membranes were all increased in the intestine when compared with SHR rats fed on a Ca-adequate diet. The equivalent enzymes in the kidneys of SHR rats, and the intestines and kidneys of WKY rats, were not affected by altering the Ca in the diet. The blood pressures of SHR rats fed on a Ca-deficient diet were higher than in those fed on a Ca-adequate diet. Blood pressures of WKY rats were not affected by altering the diet in this way. The results indicate that the absorption of Ca by active mechanisms may be reduced in SHR rats compared with WKY rats. Changing the level of Ca in the diet modified both blood pressure and the activities of enzymes which catalyse active Ca transport. The implications of these results to the aetiology, and possible nutritional treatment, of essential hypertension are discussed.     

高血压模型大鼠脂肪组织脂联素mRNA表达及福辛普利和氯沙坦干预的意义

目的 研究脂联素mRNA在自发性高血压模型大鼠脂肪组织中的表达及福辛普利和氯沙坦其表达的影响.方法 选用22周雄性高血压模型大鼠20只,随机分为高血压模型大鼠组、福辛普利干预组、氯沙坦干预组、福辛普利+氯沙坦干预组,同时选同周龄的WKY大鼠做对照组,每组动物5只,喂养8周后测大鼠尾动脉血压;留尿检测微量尿蛋白(Upm)和N-乙酰-β-D-氨基葡萄糖苷酶(NAG酶);取空腹血清检测肌酐(Scr)、尿素氮(Bun)水平;取肾周脂肪组织,RT-PCR检测脂联素mRNA表达.结果 高血压模型大鼠组血压、微量尿蛋白、NAG酶明显高于WKY组(P＜0.05),而脂联素mRNA表达明显低于WKY组(P＜0.05);药物干预组血压、微量尿蛋白、NAG酶明显低于高血压模型大鼠组(P＜0.05),而脂联素mRNA表达高于高血压模型大鼠组(P＜0.05).结论 高血压模型大鼠脂肪组织脂联素mRNA表达下降;经福辛普利和氯沙坦干预后血压下降,微量尿蛋白和NAG酶下降,肾功能改善,同时脂肪组织脂联素mRNA表达增加.提示脂联素在高血压的发生发展过程中起着重要作用.     

不同品系大鼠开场自发活动水平的研究

目的 以常用的注意缺陷多动障碍(attention deficit hyperactivity disorder,ADHD)模型自发性高血压大鼠(spontaneously hypertensive rats,SHR)为观察对象,观察其与注意缺陷多动障碍临床特征在行为学上的相似性。方法 SHR、SD(Sprague Dawley rats,SD)、WKY(Wistar Kyoto rats,WKY)大鼠各10只,利用开场实验观察记录大鼠穿越的格子数、直立次数、理毛次数、粪便颗粒数。结果 反映大鼠活动能力的穿越格数及直立次数,SHR大鼠均明显较对照组WKY、SD大鼠增多,差异有高度统计学意义(P<0.01);而表现情绪紧张程度的理毛次数和排便粒数,SHR大鼠与对照组WKY、SD大鼠的差异无统计学意义(P>0.05)。结论 SHR大鼠的多动性明显高于SD、WKY大鼠,能很好的再现注意缺陷多动障碍的多动行为学特征,是比较理想的注意缺陷多动障碍的动物模型。     

A quercetin supplemented diet does not prevent cardiovascular complications in spontaneously hypertensive rats

Diets high in quercetin may decrease the risk of developing cardiovascular disease. We tested whether quercetin delays or reduces the severity of hypertension, vascular dysfunction, or cardiac hypertrophy in the spontaneously hypertensive rat (SHR). Normotensive, 5-wk-old SHR consumed standard (n = 18) or quercetin-supplemented diet (1.5 g quercetin/kg diet, n = 22, SHR-Q) for 5 or 11 wk. Wistar Kyoto rats (WKY, n = 19), fed a standard diet, served as controls. At 16 wk, plasma quercetin, measured by HPLC, was 2.09 +/- 0.33 micromol/L in SHR-Q and below assay detection limits in SHR and WKY rats. At 10 and 16 wk of age, arterial blood pressure and heart weight:body weight were not different between SHR and SHR-Q. At 16 wk, cardiac function (echocardiography), vascular morphology (hematoxylin and eosin staining of aortae), and resistance and conductance vessel reactivity (wire myography) was unchanged in SHR vs. SHR-Q. Thus, a quercetin-supplemented diet does not delay the onset or lessen the severity of cardiovascular complications that develop in SHR. These findings contrast with previous reports of cardiovascular protection when quercetin was delivered via oral gavage. To determine whether the efficacy of quercetin depends on its method of delivery, 15-wk-old SHR were given quercetin (10 mg/kg) once daily via oral gavage for 4 consecutive days. Arterial blood pressure (mm Hg) was lower in gavaged SHR (148 +/- 5) than in SHR-Q (162 +/- 2, P < 0.02) and SHR (168 +/- 3, P < 0.001). These data suggest that mode of delivery is a critical determinant in whether quercetin provides cardiovascular benefits.     

Mineral balance and blood pressure in the young spontaneously hypertensive rat

To evaluate factors that might be related to the pathogenesis of hypertension in spontaneously hypertensive rats (SHR), mineral balance studies were conducted in SHR and control Wistar-Kyoto (WKY) rats at the ages of 9, 13 and 16 wk. During the first balance period, before onset of hypertension, Na, Ca, Mg and P balances were all significantly more positive in SHR than in WKY rats. Percentage of absorbed Na excreted in urine was correlated with the rise in blood pressure of SHR but not of WKY rats during the first 4 wk of the study. At 13 wk balances of all four nutrients still tended to be higher in SHR. During the 16th wk of life, after onset of hypertension, Na, Ca and P balances were similar in SHR and WKY rats, but Mg balance was significantly lower in SHR. The percent urinary excretion of absorbed Na was lower in SHR at 9 wk of age, but after onset of hypertension it was similar to that in WKY rats. Food intake was always greater in SHR, whereas growth during the study was less, and absorption of Ca, Mg and P declined more rapidly with age in SHR than in WKY rats. The data suggest that nutrient malabsorption in SHR, if it occurs at all, is most likely an effect of, rather than a cause of, hypertension.     

Acute effects of oral or parenteral aspartame on catecholamine metabolism in various regions of rat brain

Hypertensive (SHR) and nonhypertensive [Wistar-Kyoto (WKY); Sprague-Dawley (SD)] strains of rats received the dipeptide sweetener aspartame (200 mg/kg) or, as a positive control, tyrosine (200 mg/kg) by gavage or parenterally, after a brief (2-h) fast. Two hours later, compared with those of saline controls brain levels of the norepinephrine metabolite 3-methoxy-4-hydroxyphenylethylethyleneglycol (MHPG) sulfate were significantly higher in the hypothalamus (WKY), locus coeruleus (SD and SHR) and brain stem (SHR) in tyrosine-treated animals, and in the locus coeruleus (SD) of those given aspartame. Brain norepinephrine levels were also higher, compared with those of saline-treated control rats, in the cerebral cortex (SD and SHR), amygdala (SD) and locus coeruleus (WKY) after tyrosine administration, and in the amygdala (SD) and cerebral cortex (SHR) after aspartame administration. In another study, oral aspartame was found to be at least as effective as the parenterally administered sweetener in raising regional brain levels of tyrosine or MHPG sulfate (i.e., compared with corresponding levels in saline-treated rats). Animals receiving oral aspartame also exhibited higher plasma tyrosine and phenylalanine ratios (i.e., the ratios of their plasma concentrations to the summed concentrations of other large neutral amino acids that compete with them for uptake into the brain), than animals receiving saline.     

SHR/WKY/SD大鼠的行为学特征研究

目的 系统观察注意缺陷多动障碍(attention deficit hyperactivity disorder,ADHD)动物模型幼年SHR大鼠的注意灵活性、冲动性、自主活动性以及空间学习及记忆能力等方面的行为特征。 方法 4周龄SHR、WKY大鼠和SD大鼠各8只,适应环境1周后开始分别进行注意定势转移实验,开场实验和Morris水迷宫实验,在进行注意定势转移实验前1周,开始进行饮食限制,使测试时大鼠的体重是自由饮食组大鼠(额外8只SD大鼠)体重的85%。 结果 在注意定势转移实验中,SHR比WKY/SD大鼠的潜伏期显著性缩短(P<0.01),循环数以及固执错误和退化错误显著性增加(P<0.01)。在开场实验中,SHR与WKY比较活动水平显著性增加(P<0.01)。而与SD比较,其活动水平差异无统计学意义(P>0.05)。在定位航行实验中,SHR(14.41±3.68)s与SD大鼠(16.62±4.65)s比较其潜伏期差异无统计学意义(P>0.05),WKY(23.45±12.02)s潜伏期显著延长,表现出明显的漂浮特征。在空间探索实验中,SHR(39.92±4.68)s比WKY(54.57±9.34)s及SD(55.92±8.78)s在原平台位置停留时间显著性缩短(P<0.01)。 结论 增加SD大鼠作为另一种对照组更能准确地反应SHR大鼠在冲动性、自主活动性以及注意灵活性、空间记忆能力的特性,客观地再现了ADHD的行为特征。     

Depressed prostanoid-induced contractility of the gut in spontaneously hypertensive rats (SHR) is not affected by the level of dietary fat

Dietary saturated fat (SF) has adverse effects on cardiac and vascular smooth muscle (VSM) contractility. Furthermore, VSM of spontaneously hypertensive rats (SHR) is overreactive to various biological stimuli. The aim of this study was to investigate the effects of increasing dietary fat as lard on gut contractility in SHR. Control Wistar-Kyoto (WKY) rats and SHR (13 wk old) were fed for 12 wk a diet containing 3% sunflower oil [low fat (LF), 3% total fat] or diets supplemented with 7% lard [medium fat (MF), 10% total fat] or 27% lard [high fat (HF), 30% total fat]. For ileal and colonic tissues (WKY and SHR), there was a lower total phospholipid PUFA (n-6)/(n-3) ratio with increased dietary SF (P < 0.003). For WKY, increasing SF led to lower levels of the major SCFA and lower total SCFA levels in cecal digesta (P < 0.01). This trend was evident in SHR but significant only for butyrate (P < 0.01). Contractility responses were unaltered in ileum. In colon, there was a change of sensitivity (50% effective concentration) to angiotensin II in WKY (P < 0.05) due to increased SF and a change of sensitivity to prostaglandin (PG)E(2) and carbachol in SHR (P < 0.05). When the 3 dietary groups were combined, there was lower sensitivity (P < 0.01) and lower maximal contraction (P < 0.05) in ileum and lower maximal contraction in colon of SHR in response to PGF(2alpha) (P < 0.05) and PGE(2) (P < 0.01) compared with WKY. Unlike (n-3) PUFA, dietary SF had little overall effect on gut contractility. However, this is the first report of a defect in PG responsiveness from gut tissue from hypertensive rats.     

Effects of voluntary running exercise on blood pressure and renin-angiotensin system in spontaneously hypertensive rats and normotensive Wistar-Kyoto rats

The effect of a voluntary running exercise on blood pressure and renin-angiotensin system (RAS) was studied in male spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). SHR and WKY were assigned to either voluntary running exercise or sedentary control groups at 5 wk of age. The systolic blood pressure in the exercised group for both strains of rats was significantly lower than in the sedentary control group. The plasma renin activity (PRA) and plasma renin concentration (PRC) were significantly lower in voluntary running exercised SHR than in sedentary SHR, whereas the same exercise did not result in a lower PRA and PRC in WKY. These results suggested that the blood pressure lowering effect of voluntary running exercise is related to the suppression of RAS in SHR.     

Chronically inhaled ambient particles cause cardiac inflammation in normal, diseased, and elderly rat hearts

Exposure to ambient particulate matter (PM) is linked to increases in cardiovascular morbidity and mortality. The exact mechanism by which PM induces cardiovascular toxicity is not completely understood. We sought to study histopathological changes in the heart muscle in young healthy (Wistar–Kyoto, WKY) and spontaneously hypertensive (SHR) rats and old (22-month-old) Sprague–Dawley rats (SD) chronically exposed to PM. WKY rats and SHR were exposed for 3 months to ultrafine particles (UFP) or filtered air (FA). SD rats were exposed for 9 months to coarse (CP), fine (FP), and ultrafine particles or FA. In addition, we studied effects of PM on mean arterial blood pressure (MABP) and echocardiograms in WKY rats and SHR. Chronic exposure to PM caused histopathological changes in the hearts of all studied strains. The effects ranged from cardiac inflammation caused by 3 months of exposure to UFP in WKY rats and SHR to more severe changes in SD rats exposed to PM for 9 months. Changes in SD rats were inflammation, intracellular edema, and vacuolization in hearts exposed to FP and UFP and vacuolization and collagen accumulation in CP-exposed hearts. In addition, evidence of only mild inflammation was seen in the respiratory tract. We did not observe any statistically significant changes in the MABP (constantly recorded over the entire period of exposure by implanted telemetric devices) and in the echocardiograms in WKY rats and SHR exposed to UFP or FA. MABP at the end of 3 months exposure comprised 153.3 ± 13.9 and 160.3 ± 14.7 mmHg in the SHR-FA and SHR-UFP, respectively, and 124.4 ± 11.2 and 107.9 ± 9.2 mmHg in the WKY-FA and WKY-UFP, respectively (mean ± SD). Our data indicate that chronic exposure to particulate air pollutants causes histopathological changes in healthy (WKY), diseased (SHR), and old SD rat hearts.